216188728 has 32 divisors (see below), whose sum is σ = 490514400. Its totient is φ = 87201792.

The previous prime is 216188683. The next prime is 216188729. The reversal of 216188728 is 827881612.

216188728 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a super-2 number, since 2×216188728² = 93475132228515968, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (216188729) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 112593 + ... + 114496.

It is an arithmetic number, because the mean of its divisors is an integer number (15328575).

Almost surely, 2^216188728 is an apocalyptic number.

216188728 is a gapful number since it is divisible by the number (28) formed by its first and last digit.

It is an amenable number.

216188728 is an abundant number, since it is smaller than the sum of its proper divisors (274325672).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

216188728 is a wasteful number, since it uses less digits than its factorization.

216188728 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 227119 (or 227115 counting only the distinct ones).

The product of its digits is 86016, while the sum is 43.

The square root of 216188728 is about 14703.3577117609. The cubic root of 216188728 is about 600.1746972780.

The spelling of 216188728 in words is "two hundred sixteen million, one hundred eighty-eight thousand, seven hundred twenty-eight".